WASHINGTON — The Defense Department on March 4 will propose a five-year plan that boosts Pentagon spending by a total of $115 billion over sequestration spending caps, according to multiple sources who have been briefed on the plan.

Defense Secretary Chuck Hagel on Monday will preview the plan, along with other key items included in DoD's $496 billion 2015 budget proposal. The budget proposal ignores federally mandated spending caps between 2016 and 2019. Sister publication Defense News has reported that the fiscal 2016 budget projection would be $36 billion over the sequester cap.

While DoD's fiscal 2015 budget falls in line with defense spending caps for that year, the budget will include a separate $26 billion "Opportunity, Growth and Security Initiative." The additional $26 billion would go toward readiness, the sources said.

The proposal recommends keeping an aircraft carrier but sidelining half of the Navy's cruiser fleet. It would also retire the Air Force's A-10 and U-2 fleets and sets the stage for retiring the KC-10 fleet and for delaying the Navy's version of the F-35.

Reached Sunday night, Pentagon press secretary Rear Adm. John Kirby said he would not comment on budget specifics ahead of Hagel's rollout.

"The Secretary believes strongly that we are facing unique challenges today, both from a security perspective and from a fiscal one. He further believes it is important that a budget not just state what you will pay for, but also what you will stand for," Kirby said. "He has worked hard with the services to ensure that we continue to stand for the defense of our national interests — that whatever budget priorities we establish, we do so in keeping with our defense strategy and with a strong commitment to the men and women in uniform and to their families.

"But he has also said that we have to face the realities of our time. We must be pragmatic. We can't escape tough choices. He and the chiefs are willing to make those choices — choices that become impossible to make intelligently should sequestration remain the law of the land."

As for the additional $26 billion, an Obama administration official said the initiative "will be fully paid for with a balanced package of spending and tax reforms."

The funding should not be considered an unfunded priorities, or wish list, the official said.

"It will demonstrate how, by simply closing a few unfair tax loopholes and reforming spending programs, Congress could achieve significant economic goals in research, education, manufacturing and skills training," the official said. "It will be evenly split between defense and non-defense.

"This is consistent with the model established in Murray-Ryan, providing equal dollar-for-dollar increases above the current law discretionary spending caps for both defense and non-defense," the official continued, referring to the spending compromise hashed out by Sen. Patty Murray, D-Wash., and Rep. Paul Ryan, R-Wis. "This level would fully eliminate the remaining non-defense discretionary sequestration cuts in FY2015."

The five-year projections included in the budget are not in line with federal spending caps and would be subject to sequestration if the law is not changed.

DoD intends to slash personnel across all of the military services, but plans to add nearly 4,000 to the special operations ranks. The spending forecast calls for reducing the Army to between 440,000 to 450,000 soldiers and going as low as 420,000 if sequester remains. It also proposes shrinking the Marine Corps by 8,000 Marines to 182,000. Total Corps end-strength drops to 175,000 if sequestration continues.

The budget plan proposes cutting 20,000 from the Army National Guard — dropping to 335,000 by 2019 — and 10,000 from the Army Reserve, bring it to 195,000.

DoD will ask Congress to approve a base realignment and closure (BRAC) round in 2017. This spring, DoD will begin a review of its infrastructure in Europe to recommend funding cuts on the continent, which are not subject to BRAC.

Defense officials say DoD still plans to fulfill its commitments in Europe and the Middle East.

In terms of service specifics, the Pentagon is planning to invest $1 billion in next-generation jet engine technology.

As has been widely reported, the Air Force would retire its entire A-10 attack jet fleet. If sequestration remains in place, it would also retire its entire KC-10 fleet and reduce unmanned aircraft combat air patrols.

The Air Force also will propose retiring its entire Lockheed Martin U-2 spy plane fleet, which sources said was tirelessly debated throughout the budget-building process. It will instead opt to replace the U-2 with the unmanned Northrop Grumman Global Hawk surveillance aircraft, a reversal of what the Air Force had wanted to do.

The Navy will not ask to retire an aircraft carrier, as had been reported. Yet it will not fund the midlife refueling of the carrier George Washington. Instead, DoD will make a decision on whether to cut an aircraft carrier from its 11-ship fleet in 2016, sources said.

The Navy also will propose taking 11 cruisers — half the fleet — out of service until funds are available to modernize them.

The Navy plans to purchase two submarines and two destroyers per year, as well as an additional afloat staging base.

If sequestration continues, the Navy would have to lay up six additional ships in 2016. It would also suspend purchases of the F-35C carrier-based version of the Joint Strike Fighter for two years, sources said.